Nintendo formally announced Wii U's year-end 2012 release period today and also shared details specs for the system. View the full spec sheet at Nintendo's special E3 site, along with an Iwata Asks column about the hardware, and a video detailing the Wii U GamePad.

Nintendo did not share a specific release date or price for the Wii U system. However, the hardware page does seem to indicate that the system will be offered in black or white color variations.

Included in the spec sheet is a detailed breakdown for the systems' GamePad.

Input methods include touch screen, L and R sticks, L and R stick buttons, d-pad, A, B, X, Y, L and R, ZL and ZR, +/Start, -/Select, and motion controls (accelerometer, gyro sensor, geomagnetic). Other inputs include power button, home button, synch button, volume (for the GamePad's stereo audio output) and TV control button. The device also has rumble, a built in camera, a built in mic, a sensor bar, and NFC read/write functionality.

Battery life for the GamePad is 3 to 5 hours. This changes depending on the screen brightness. You can also play while charging the GamePad via the included AC Adapter. Charge time is 2 hours 30 minutes.

The system itself measures 46 x 172 x 268.5mm and weighs 1.5kg. It has an IBM CPU and AMD Radeon GPU.

Control options include Wii U Game Pad, WiiMote (or WiiMote Plus) and Wii U Pro Controller. These latter two can have four devices connected simultaneously (Nintendo said at today's press conference that two Wii U Gamepads can be used simultaneously, but this is not mentioned in the spec sheet). Wii U can also work with all the various Wii controllers, including Nunchucks and Balance Wii Board.

The system has built in flash storage. You can also use SD Memory cards and external USB storage devices.